Blade holder

ABSTRACT

Blade holder for creping of a web travelling on a rotating cylinder (2) or for doctoring the surface of the cylinder, comprising a blade (3) directed opposite to the travelling direction of the cylinder (2), a blade carrier (41) for the blade, further comprising a pressure ledge (13) extending along the whole length of the blade and arranged to exert a pressure at or adjacent to the upper longitudinal edge of the blade (3) via pivotable pressure arms (15) evenly distributed along the length of the ledge and arranged on the blade carrier (41) to bring said edge to engagement against the cylinder (2). Each pressure arm (15) is arranged to be individually actuated by a pressure means having a double folded membrane (35) for actuation of the pressure arm (15) by means of a pressure medium.

The present invention relates to a blade holder for creping of a web,particularly a paper web, travelling on a rotating cylinder, or fordoctoring a rotating cylinder surface.

The development in the paper manufacture technology has resulted indemands for ever increasing production rates coupled to increasing webwidths. Today plants are installed having paper speeds of up to 1500m/min and with paper widths which in some cases are up to 8 m or more.Such plants require great precision with regard to blade suspension andpossibility of section-wise individual adaptation of the engagementpressure of the blade across the whole width of the web. Furthermore,the high costs associated with even short standstill of a large machinerequire that machine maintenance in the form of for example bladereplacement can be carried out quickly and effectively with a minimum oftime waste. Furthermore, there is required for obtaining optimalfunction the possibility of adjusting the blade angle of attack inrelation to the cylinder on which the paper web is fed in a simplemanner.

The present invention has for its object to provide a blade holderdevice for creping of web travelling on a rotating cylinder or fordoctoring a cylinder surface, said device meeting high demands in therespects as indicated above.

Accordingly, the invention has for a primary object to provide a bladeholder for creping of a travelling web, particularly a paper web,wherein the engagement pressure of the blade on the cylinder carryingthe travelling web can be adjusted along the whole length of the bladewithout changing the blade angle of attack against the cylinder surface.

Another object of the invention is to provide a blade holder enablingeasy exchange of blade at a minimum of time.

Yet an object of the invention is to provide a blade holder by which theblade angle of attack against the cylinder carrying the travelling webcan be varied in a simple manner without affecting other parameters.

Another object is to provide for a simple method of adjusting the bladeholder for varying blade widths.

A further object is to provide possibility for section-wise individualadjustement of the engagement pressure of the blade against thecylinder.

For these and other objects which will be clear from the followingdescription there is provided through the present invention a bladeholder for creping of a web, particularly a paper web, travelling on arotating cylinder, or for doctoring the surface of the cylinder,comprising a blade directed opposite to the travelling direction of thecylinder, a blade holder for the blade, further comprising a pressureledge extending along the whole length of the blade and arranged toexert a pressure at or adjacent to the upper longitudinal edge of theblade via pivotable pressure arms evenly distributed along the length ofthe ledge and arranged on the blade holder to bring said edge toengagement against the cylinder. Said blade holder is characterized inthat each pressure arm is arranged to be individually actuated by apressure means having a double folded membrane for actuation of thepressure arm by means of a pressure medium.

According to a preferred embodiment of the blade holder according to theinvention each pressure arm has associated therewith an individuallyadjustable counter-pressure means whereby the actuation of the blade bythe pressure means can be balanced.

In a particularly preferred embodiment of the blade holder according tothe invention the membrane is provided with a double folded annularmember, said member comprising a central section surrounded by saidmember cooperating with a stop member fixed onto the blade holder, and aring-shaped section surrounding the annular section, said ring-shapedsection being leak-tight connected to a surrounding ring element, saidmembrane and a corresponding lid element together with the ring elementdefining a pressure chamber which, via an opening, can be pressurized toa desired pressure by means of a pressure medium, said pressureaffecting the associated pressure arm via the ring element.

With regard to the blade holder and the attachment of the blade to theholder it is preferred that the blade holder comprises a blade carrierledge provided with a groove or recess extending along the whole lengthof the blade carrier ledge and having a depth short of the width of theblade and widening outwardly so that the blade with its lowerlongitudinal edge contained in the groove or recess in the absence ofexterior influence can tilt and move freely towards or away from thecylinder.

It is, moreover, preferred that the blade holder comprises a carrierbeam carrying guide ledges extending along the whole length of the bladeand between which the blade can be displaced upwardly towards thecylinder synchronously with the wear of the blade.

Furthermore, the carrier beam suitably carries jackscrews whereby theblade carrier ledge is continuously displacable towards the cylinder inaccordance with the wear of the blade.

In this context it is particularly preferred that each jackscrew isprovided with an adjustment nob with a scale which is graduated in sucha manner as to show the distance between the point of engagement of theblade against the cylinder and the bottom of the recess of the bladecarrier ledge thus giving a measure of the width of the blade.

In a preferred embodiment of the blade holder according to the inventionthe press ledge is arranged to exert its pressure adjacent to thelongitudinal edge of the blade engaging the cylinder so as to impart noessential bending of the blade. In order to obtain such condition it issuitable that the pressure of the press ledge against the blade isexerted along a line at a distance of less than about 15 mm andpreferably 3-8 mm from the point of contact of the blade with thecylinder.

In yet another preferred embodiment of the blade holder according to theinvention it comprises suspension arms for the carrier beam arranged ateach end of the blade holder each provided with two legs and attached tothe carrier beam at the ends thereof, one leg being pivotably connectedto a fixed element, whereas the other leg via a first positionadjustment means can be raised or lowered for controlling the bladeangle in relation to a tangent to the surface of the cylinder, and thepivot center (C) being positioned in the point of attachment between theblade and the cylinder. By this arrangement the attack angle of theblade can thus be varied without changing other conditions.

For the purpose of enabling maintenance, for example exchange of blade,it is preferred that the blade holder according to the inventioncomprises a rocking means, whereby the blade with the carrier beam canbe moved between an operating position and an inoperative position, saidrocking means comprising link arms arranged at each end of the carrierbeam which at one end thereof are pivotably connected and one link armat the opposite end thereof is pivotably connected to a pivot arm whichis fixed to the rotary shaft of the carrier beam and the opposite end ofthe other link arm is pivotably connected to the suspension arm, asecond position adjustment means being arranged on the latter armcapable of moving the pivotable point of attachment of the link arms toa rectilinear operative position or an angular inoperative position.

In a particularly preferred embodiment of this device the secondposition adjustment means is pivotably connected to the suspension armand is constituted by a hydraulic or pneumatic cylinder having a pistonand a piston bar at the free end of which said one end of the link armsis pivotably connected. Furthermore, the position adjustment means issuitably connected to the fixed element, whereas the opposite end of thesecond link arm preferably is connected to a first projection on thesecond leg.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further illustrated in connection to apreferred embodiment and with reference to the appended drawings,wherein:

FIG. 1 is a sideview diagrammatically illustrating a blade holder inaccordance with the invention;

FIG. 2 shows said embodiment with the blade in an inoperative position;

FIG. 3 shows more in detail and in an enlargement the arrangement aroundthe blade carrier and the blade; and

FIG. 4 shows a detail in enlargement of the blade carrier with carrierbeam and operative means associated with the blade.

DETAILED DESCRIPTION OF THE DRAWINGS

With particular reference to FIGS. 1 and 2 the embodiment of the bladeholder according to the invention illustrated in the drawings comprisesa blade carrier device generally designated 1 carrying a blade 3, forexample intended for the creping of a paper web, said blade in turnresting on a blade carrier ledge 5, especially in a groove or recess 11arranged at the upper part of said ledge. As is clear from for exampleFIG. 3 said recess 11 extends along the whole length of the bladecarrier ledge 5 and has a depth substantially short of the width of theblade and widening upwardly in such a manner that blade 3 with its lowerlongitudinal edge contained in the recess in the absence of outerinfluence can tilt and move freely towards or away from a cylinder 2 onwhich the travelling web is carried.

The blade carrier ledge 5 is placed between two guide members 7,9extending along the whole length of the blade carrier ledge and theblade.

As is clear from FIG. 4 the supporting function of the blade carrier isprovided by a beam profile 41 with an upper plate 43 arranged on top ofsaid profile, the blade 3 and associated guide members 7,9 being placedon said plate.

As is clear from FIG. 3 the blade carrier ledge 5 can be moved upwardlysynchronously with the wear of the blade 3 by at least two adjustmentdevices generally designated 45 arranged at both ends of the bladecarrier ledge 5. The adjustment device 45 includes a worm gear 47 with ascrew 49 and a cooperating tooth wheel 51 rotatable around an axis 53 bymeans of a handle wheel 55 with a handle 57. The screw 49 is at itsupper end provided with a threaded section 59 cooperating with acorresponding interior thread in the blade carrier ledge 5. The handlewheel 55 is provided with a graduated scale 56 which is graduated insuch a manner that it shows the distance between the point C ofengagement of the blade 3 against the cylinder 2 and the bottom of therecess 11 of the blade carrier ledge 5, said distance being equal to thewidth of the blade.

In order to provide the engagement of the blade 3 against the cylinder 2the illustrated embodiment contains as is clear from FIG. 2 a pressledge 13 extending along the whole length of the blade 3. This pressledge 13 is carried by angle arms 15 which are pivotable around a pivot21 and each comprise an upwardly directed part 17 and a horisontal part19. The pivot 21 is anchored in a pivot attachment 23 in turn connectedto the guide member 7. Each angle arm 15 can be selectively actuated byan upward force affecting the horisontal part 19 of the angle arm 15.This force actuation is provided by a device positioned in a recess 31in the horisontal part 19 of each angle arm 15. This device is brieflydesigned in the following manner.

As is clear from FIG. 3 pressure actuation is provided by adouble-folded membrane 35 comprising a double-folded annular section 39,a central section 40 surrounded by said annular section and cooperatingwith a fixed stop member 37 in the form of an upwardly directed cylinderarranged on the upper plate 43 on the carrier beam 41. Furthermore, themembrane includes a ring-shaped section 42 surrounding the annularsection 39 and tightly connected to a surrounding ring element 44.Together with an opposite lid element 46 membrane 35 defines togetherwith the ring element 44 a pressure chamber 33 which via an opening 48in the lid element 46 can be pressurized to a desired pressure by meansof a pressure medium. The pressurization of the pressure chamber 33which can be provided by hydraulic or pneumatic means affects via thering element 44 the corresponding angle arm 15 to press blade 3 viapress ledge 13 against the cylinder 2. It is important to note that thepressure device just described provides an upward force on thehorisontal part 19 of the angle arm 15 which is only determined by thepressure generated by the pressure medium irrespective of the positionof the horisontal part 19 in relation to the fixed stop member 37. Byusing a double-folded membrane 35 every influence of the elasticityproperties of the membrane material will thus be avoided and a movementof the horisontal part of angle arm 15 essentially free of friction willbe provided.

As is further clear from FIG. 3 the blade holder device is provided witha counter pressure member 25 with associated spring 27, the pressuregenerated by the membrane device being counteracted to the desireddegree. In this manner there is obtained a balanced engagement pressureof the blade via the pressure ledge 13 in view of the fact that thecounterpressure by counterpressure member 25 can be controlled bypresetting of the counterpressure member 25, for example by arrangingmember 25 with threads in the angle arm 15 thereby making same possibleto preset. The devices just described are contained below a cover sheet29 extending along the whole length of the carrier beam 41.

As is clear from FIG. 1 the carrier beam 41 is carried via its shafts 81by suspension arms 61 arranged at each end of the blade holder. Eachsuspension arm 61 is provided with two legs, one upwardly directed leg63 and one horisontal leg 65. The upwardly directed leg 63 is pivotablyconnected by a pivot 69 to an upper beam 71 via a pivot attachment 67attached to the beam 71. The second leg can via a first positionadjustment device generally designated 76 be lifted or lowered for apurpose to be described below. The position adjustment device 76comprises two jackscrews 77 with handle wheels 80 coupled in parallel,said screws being pivotably arranged in a pivot attachment 79 connectedto the upper beam 71. The screw 75 of jack 77 is pivotably connected tothe horisontal leg 65 of the suspension arm 61 via a pivot 73.

As is clear from FIG. 1 the angle of attack of the blade againstcylinder 2 can be varied by means of the position adjustment device 76,and this without changing the contact line and the contact pressureagainst cylinder 2. This is provided by the fact that the center for theswing movement, i.e. the center of pivot 69, coincides with the contactpoint C between blade 3 and cylinder 2.

As is clear from FIGS. 1 and 2 the embodiment of the blade holderaccording to the invention is provided with a swing device, whereby theblade 3 with the carrier beam 41 can be moved between an operatingposition (FIG. 1) and an inoperative position (FIG. 2) in order toenable some maintenance, for example exchange of blade. This swingdevice generally designated 85 comprises link arms 87,89 arranged ateach end of the carrier beam 41, said link arms at one end thereof beingpivotably connected to each other via a pivot 91. The opposite end ofone link arm 89 is pivotably connected to a lever 105 which is fixed tothe pivot or shaft 81 of the carrier beam, whereas the other end of theother link arm 87 is pivotably connected to the horisontal leg 65 of thesuspension arm 61 via an extension 101 on said leg.

The swing device 85 further comprises a second position adjustmentdevice generally designated 86. This second position adjustment device86 comprises a hydraulic or pneumatic cylinder 95 with piston (notshown) and piston bar 93 at the free end of which the mutually connectedends of the link arms 87,89 are pivotably attached via a pivot 91. Thehydraulic or pneumatic cylinder 95 is pivotably connected to thehorisontal leg of the suspension arm 61 via a second extension 97.

While manoeuvring hydraulic or pneumatic cylinder 95 with withdrawal ofpiston bar 93 the blade holder can be adjusted to the position shown inFIG. 2, i.e. an inoperative position enabling for example exchange ofblade. By extension of the piston bar 93 the blade 3 can be returned toan operative position according to FIG. 1, and this position can beexactly determined by bringing the link arms 87,89 to a rectilinearposition according to FIG. 1. This position can be easily reached by thepiston of cylinder 95 taking an end position where link arms 87,89 takethe rectilinear position which is shown in FIG. 1.

The embodiment described provides for substantial advantages whichbriefly are the following.

By means of the arrangement around the pressing ledge 13 the blade canover its entire length be brought to engagement against the cylinder 2section-wise and individually to obtain an even engagement and crepingor doctoring effect over the whole length of the blade. This can be donewith great accuracy by the use of the roll membrane 35 in combinationwith the counter member 25. Furthermore, by means of the adjustmentdevice 45 the blade can be progressively lifted in pace with the wearand with simultaneous control of the remaining width of the blade.

By means of the first position adjustment device 76 the attack angle ofthe blade 3 against the cylinder 2 can be varied without changing thepoint of engagement and the engagement pressure of the blade against thecylinder will be changed.

Finally, by means of the second position adjustment device 86 the bladetogether with the carrier beam 41 can in a simple manner be moved to theinoperative position shown in FIG. 2, whereby for example exchange ofblade easily can be carried out.

The blade holder according to the present invention thus offers improvedflexibility under operation, a more even creping over the whole lengthof the blade, less waste of time in connection with maintenance, bladeexchange etc., and simplified possibility of variation of the attackangle of the blade.

It should be observed that the present invention is not restricted tothe embodiment described above and that its scope is limited only by thecontents of the appended claims. The skilled artisan easily realizes howthe device can be modified in different ways within the framework of theinventive concept.

What is claimed is:
 1. Blade holder for creping of a web travelling on arotating cylinder or for doctoring the surface of the cylinder,comprising a blade directed opposite to the travelling direction of thecylinder, a blade carrier for the blade, further comprising a pressureledge extending along the whole length of the blade and arranged toexert a pressure at or adjacent to the upper longitudinal edge of theblade via pivotable pressure arms evenly distributed along the length ofthe ledge and arranged on the blade carrier to bring said edge toengagement against the cylinder, wherein each pressure arm is arrangedto be individually actuated by a pressure means having a membrane foractuation of the pressure arm by means of a pressure medium, furthercomprising a blade carrier ledge provided with a groove or recess at theupper part thereof extending along the whole length of the blade carrierledge and having a depth short of the width of the blade and wideningoutwardly so that the blade with its lower longitudinal edge containedin the groove or recess in the absence of exterior influence can tiltand move freely towards or away from the cylinder.
 2. Blade holderaccording to claim 1, wherein each pressure arm has associated therewithan individually adjustable counter pressure means.
 3. Blade holderaccording to claim 1, wherein the blade carrier comprises a carrier beamsupporting guide ledges extending along the whole length of the bladeand between which the blade can be displaced upwardly towards thecylinder synchronously with the wear of the blade.
 4. Blade holderaccording to claim 3, wherein the carrier beam carries jackscrewscoupled in parallel, whereby the blade carrier ledge is continuouslydisplaceable towards the cylinder in accordance with the wear of theblade.
 5. Blade holder according to claim 5, wherein each jackscrew isprovided with an adjustment nob provided with a scale which is graduatedin such a manner as to show the distance between the point of engagementof the blade against the cylinder and the bottom of the recess of theblade carrier ledge, equal to the width of the blade.
 6. Blade holderaccording to claim 1, wherein the pressure ledge is arranged to exertits pressure so near to the longitudinal edge of the blade that noessential bending of the blade takes place.
 7. Blade holder according toclaim 1, comprising suspension arms for the carrier beam arranged ateach end of the blade holder, each provided with two legs and attachedto the carrier beam at the ends thereof, one leg being pivotablyconnected to a fixed element, whereas the other leg via a first positionadjustment means can be raised and lowered for controlling the angle ofthe blade in relation to a tangent to the surface of the cylinder, andthe pivot center being positioned in the point of attachment between theblade and the cylinder.
 8. Blade holder according to claim 1, comprisinga rocking means, whereby the blade with the carrier beams can be movedbetween an operating position and an inoperative position so as toenable maintenance, said rocking means comprising link arms arranged ateach end of the carrier beam which at one end thereof are pivotablyconnected to a pivot arm which is fixed to the rotary shaft o thecarrier beam, and the opposite end of the other link arm being pivotablyconnected to the suspension arm, a second position adjustment meansbeing arranged which can move the pivotable point of attachment of thelink arms to a rectilinear operative position of an angular inoperativeposition.
 9. Blade holder according to claim 8, wherein the secondposition adjustment means is pivotably connected to the suspension armand is constituted by a hydraulic or pneumatic cylinder having a pistonand a piston bar at the free end of which said one end of the link armsis pivotably connected.
 10. Blade holder according to claim 7, whereinthe position adjustment means is connected to the fixed element. 11.Blade holder according to claim 8, wherein the opposite end of thesecond link arm is attached to a first extension on the second leg. 12.Blade holder according to claim 9, wherein the cylinder is pivotablyconnected to a second extension on the second leg.
 13. Blade holderaccording to claim 2, wherein the pressure ledge is arranged to exertits pressure so near to the longitudinal edge of the blade that noessential bending of the blade takes place.
 14. Blade holder accordingto claim 2, comprising suspension arms for the carrier beam arranged ateach end of the blade holder, each provided with two legs and attachedto the carrier beam at the ends thereof, one leg being pivotablyconnected to a fixed element, whereas the other leg via a first positionadjustment means can be raised or lowered for controlling the angle ofthe blade in relation to a tangent to the surface of the cylinder, andthe pivot center being positioned in the point of attachment between theblade and the cylinder.
 15. Blade holder according to claim 19, whereinthe opposite end of the second link arm is attached to a first extensionon the second leg.
 16. Blade holder according to claim 10, wherein thecylinder is pivotably connected to a second extension on the second leg.17. Blade holder for creping of a web travelling on a rotating cylinderor for doctoring the surface of the cylinder, comprising a bladedirected opposite to the travelling direction of the cylinder, a bladecarrier for the blade, further comprising a pressure ledge extendingalong the whole length of the blade and arranged to exert a pressure ator adjacent to the upper longitudinal edge of the blade via pivotablepressure arms evenly distributed along the length of the ledge andarranged on the blade carrier to bring said edge to engagement againstthe cylinder, wherein each pressure arm is arranged to be individuallyactuated by a pressure means having a membrane for actuation of thepressure arm by means of a pressure medium, wherein the membrane isprovided with a double folded annular member, a central sectionsurrounded by said member and cooperating with a stop member fixed ontothe blade carrier, and a ring-shaped section surrounding the annularsection which is leak-tight connected to a surrounding ring element,said membrane and an opposite lid element together with the ring elementdefining a pressure chamber which, via an opening, can be pressurized toa desired pressure by means of a pressure medium, said pressureaffecting the associated pressure arm via the ring element.
 18. Bladeholder for creping of a web travelling on a rotating cylinder or fordoctoring the surface of the cylinder, comprising a blade directedopposite to the travelling direction of the cylinder, a blade carrierfor the blade, further comprising a pressure ledge extending along thewhole length of the blade and arranged to exert a pressure at oradjacent to the upper longitudinal edge of the blade via pivotablepressure arms evenly distributed along the length of the ledge andarranged on the blade carrier to bring said edge to engagement againstthe cylinder, wherein each pressure arm is arranged to be individuallyactuated by a pressure means having a membrane for actuation of thepressure arm by means of a pressure medium, wherein each pressure armhas associated therewith an individually adjustable counter pressuremeans, and wherein the membrane is provided with a double folded annularmember, a central section surrounded by said member and cooperating witha stop member fixed onto the blade carrier, and a ring-shaped sectionsurrounding the annular section which is leak-tight connected to asurrounding ring element, said membrane and an opposite lid elementtogether with the ring element defining a pressure chamber which, via anopening, can be pressurized to a desired pressure by means of a pressuremedium, said pressure affecting the associated pressure arm via the ringelement.
 19. Blade holder for creping of a web travelling on a rotatingcylinder or for doctoring the surface of the cylinder, comprising ablade directed opposite to the travelling direction of the cylinder, ablade carrier for the blade, further comprising a pressure ledgeextending along the whole length of the blade and arranged to exert apressure at or adjacent to the upper longitudinal edge of the blade viapivotable pressure arms evenly distributed along the length of the ledgeand arranged on the blade carrier to bring said edge to engagementagainst the cylinder, wherein each pressure arm is arranged to beindividually actuated by a pressure means having a membrane foractuation of the pressure arm by means of a pressure medium, whereineach pressure arm has associated therewith an individually adjustablecounter pressure means, and further comprising a blade carrier ledgeprovided with a groove or recess at the upper part thereof extendingalong the whole length of the blade carrier ledge and having a depthshort of the width of the blade and widening outwardly so that the bladewith its lower longitudinal edge contained in the groove or recess inthe absence of exterior influence can tilt and move freely towards oraway from the cylinder.